Optical Coating Method, Apparatus and Product

ABSTRACT

This disclosure is directed to an improved process for making glass articles having optical coating and easy-to clean coating thereon, an apparatus for the process and a product made using the process. In particular, the disclosure is directed to a process in which the application of the optical coating and the easy-to-clean coating can be sequentially applied using a single apparatus. Using the combination of the coating apparatus and the substrate carrier described herein results in a glass article having both optical and easy-to-clean coating that have improved scratch resistance durability and optical performance, and in addition the resulting articles are “shadow free.”

PRIORITY

This application is a continuation application, under 35 U.S.C. §120, ofU.S. utility application Ser. No. 14/022,792 titled “Optical CoatingMethod, Apparatus And Product” filed Sep. 10, 2013, which is acontinuation application, under 35 U.S.C. §120, of U.S. UtilityApplication Ser. No. 13/690,829 titled “Optical Coating Method,Apparatus and Product” filed Nov. 30, 2012, which in turn, claims thebenefit of priority under 35 U.S.C. §119 of U.S. Provisional ApplicationNo. 61/709,423 titled “Optical Coating Method, Apparatus and Product”filed Oct. 4, 2012, and of U.S. Provisional Application No. 61/565,024titled “Process for Making of Glass Articles With Optical andEasy-To-Clean Coatings” filed Nov. 30, 2011, the contents of which arerelied upon and incorporated herein by reference in their entirety.

FIELD

This disclosure is directed to a process for making glass articleshaving an optical coating and an easy-to-clean (ETC) coating thereon, anapparatus for performing the process and an article made using theprocess. In particular, the disclosure is directed to a process in whichthe application of the optical coating and the ETC coating can besequentially carried out using the same apparatus.

BACKGROUND

Glass, and in particular chemically strengthened glass, has become thematerial of choice for the view screen of many, if not most, consumerelectronic products. For example, chemically strengthened glass isparticularly favored for “touch” screen products whether they be smallitems such as cell phones, music players, eBook readers and electronicnotepads, or larger items such as computers, automatic teller machines,airport self-check-in machines and other similar electronic items. Manyof these items require the application of antireflective (“AR”) coatingson the glass in order to reduce the reflection of visible light from theglass and thereby improve contrast and readability, for example, whenthe device is used in direct sunlight. However, some of the drawbacks ofan AR coating are its sensitivity to surface contamination and its pooranti-scratch durability, that is, the AR coating becomes easilyscratched during use, for example, by a wiping cloth or the dirt andgrime on a user's finger. Fingerprints and stains are very noticeable onan AR coated surface and are not always easily removed. As a result, itis highly desirable that the glass surface of any touch device be easyto clean which is achieved by applying an easy-to-clean (ETC) coating tothe glass surface.

The current processes for making glass articles having bothantireflection and ETC coatings requires that the coating be appliedusing different equipment, and consequently separate manufacturing runs.The basic procedure is to apply the antireflection (“AR”) coating to aglass article using, for example, a chemical vapor (“CVD”) or physicalvapor deposition (“PVD”) method. In conventional processes, an opticallycoated article, for example, one with an AR coating, will be transferredfrom the optical coating apparatus to another apparatus to apply the ETCcoating on top of the AR coating. While these processes can producearticles that have both an AR and an ETC coating, they require separateruns and have higher yield losses due to the extra handling that isrequired. This may result in poor reliability of the final product dueto contamination arising from the extra handling between the AR coatingand ETC coating procedures. For example, using the conventional 2-stepcoating process of ETC over an optical coating results in an articlethat is easily scratched in touch screen applications. In addition,while the AR coated surface can be cleaned before applying the ETCcoating, this involves additional steps in the manufacturing process.All the additional steps increase the product costs. Consequently,alternative methods and apparatuses are needed by which both coatingscan be applied using the same basic procedure and equipment, thusreducing manufacturing costs. Advantages of the process disclosed hereinand resulting products are set forth in the following paragraphs andclaims.

SUMMARY

In one embodiment, the disclosure provides a method for making a glassarticle having an optical coating and an easy-to-clean coating on top ofthe optical coating includes providing a coating apparatus having avacuum chamber for the deposition of an optical coating and an ETCcoating, providing a magnetic rotatable dome within said chamber formagnetically positioning a magnetic substrate carrier for receiving aglass substrate thereon that is to be coated, and providing within saidvacuum chamber source materials for the optical coating and sourcematerials for the ETC coating. The method also includes loading theglass substrate on the magnetic substrate carrier and magneticallyattaching the magnetic substrate carrier having the glass substratethereon to the dome, evacuating the vacuum chamber, rotating the domeand depositing an optical coating on the glass substrate, and rotatingthe dome and depositing the ETC coating on top of the optical coatingfollowing deposition of the optical coating, where the optical coatingis not exposed to ambient atmosphere prior to the deposition of the ETCcoating. The method further includes removing the substrate having theoptical coating and the ETC coating from the chamber to obtain a glasssubstrate having a shadow-free optical coating deposited on thesubstrate and an ETC coating deposited on the optical coating.

In another embodiment, the disclosure provides a magnetic substratecarrier for holding a substrate during a coating process, where themagnetic substrate carrier includes a non-magnetic substrate carrierbase having a plurality of magnets attached to the non-magnetic carrierbase, a plurality of pins for supporting a surface of a glass substratepositioned on the substrate carrier, and a spring system that includes aretractable pin held in place by a spring that retracts the retractablepin, where the retractable pin is extendable in a direction opposite thespring. The spring system also includes a plurality of fixed pins and aplurality of stoppers extending from the non-magnetic substrate carrierbase for a distance such that, when the glass substrate is positioned onthe plurality of pins, the tops of the stoppers are below a top surfaceof the glass substrate.

In yet another embodiment, the disclosure provides a magnetic carrierfor holding substrates during a coating process, where the substratecarrier includes a non-magnetic carrier base, a plurality of magnetsattached to the non-magnetic carrier base, and a plurality of pins forsupporting a surface of a glass substrate. The substrate carrier alsoincludes a housing for a retractable pin and a retractable pin disposedin the housing, where the retractable pin is held in place by a springand the retractable pin is outwardly biased from the housing, optionalstoppers, and a plurality of movable pins for holding an edge of theglass article.

In yet another embodiment, the disclosure provides a glass articlehaving an optical coating and an easy-to-clean coating on top of theoptical coating, where the glass article is shadow free across anoptically coated surface of the glass article. The optical coatingincludes a plurality of periods consisting of a layer of high refractiveindex material H having an index of refraction n greater than or equalto 1.7 and less than or equal to 3.0, and a layer of low refractiveindex material L having an index of refraction n greater than or equalto 1.3 and less than or equal to 1.6. The layer of high refractive indexmaterial is the first layer of each period and the layer of lowrefractive index material L is the second layer of each period. An SiO₂capping layer having a thickness in the range greater than or equal to20 nm and less than or equal to 200 nm is applied on top of theplurality of periods.

In another embodiment, the disclosure provides a coating apparatus forcoating a substrate with an optical coating and an ETC coating. Thecoating apparatus may include: a vacuum chamber; a magnetic rotatabledome positioned in the vacuum chamber; at least one e-beam sourcepositioned in the vacuum chamber; at least one thermal evaporationsource positioned in the vacuum chamber; and a shadow mask adjustablypositioned on a support within the vacuum chamber.

Additional features and advantages of the methods described herein willbe set forth in the detailed description which follows, and in part willbe readily apparent to those skilled in the art from that description orrecognized by practicing the embodiments described herein, including thedetailed description which follows, the claims, as well as the appendeddrawings.

It is to be understood that both the foregoing general description andthe following detailed description describe various embodiments and areintended to provide an overview or framework for understanding thenature and character of the claimed subject matter. The accompanyingdrawings are included to provide a further understanding of the variousembodiments, and are incorporated into and constitute a part of thisspecification. The drawings illustrate the various embodiments describedherein, and together with the description serve to explain theprinciples and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic drawing of a coating apparatus 100 according toone or more embodiments described herein;

FIG. 1B schematically depicts an enlarged view of glass plate 116 andillustrates the opening 116 a for receiving a quartz monitor;

FIG. 1C schematically depicts an enlarged view of the glass plate withthe quartz monitor received within the opening and an optical fiber,both of which are used to measure and control the deposition of theoptical coating materials onto glass substrates attached to a substratecarrier;

FIG. 2 is a drawing representing a top-down view through a section ofthe dome of the coating apparatus of FIG. 1A illustrating a plurality ofsubstrate carriers magnetically attached to the dome;

FIG. 3A schematically depicts an oblique bottom-up side view of asegment of the dome of the coating apparatus of FIG. 1A with a pluralityof substrate carriers magnetically attached to the dome;

FIG. 3B schematically depicts a frame that supports the dome segments110 a; frame 160 having an outer lip/rim 161 as is also illustrated inFIG. 3A, an inner rim (not numbered) at opening 164 to which therotation shaft 117 can be attached (not illustrated) and a plurality ofspokes 162 that are sufficiently wide to accommodate the side edges ofthe dome segments as is illustrated at 168;

FIG. 4A schematically depicts a non-magnetic substrate carrier 130having a plurality of elements 134 for magnetically attaching thecarrier to dome 110 and for holding a glass substrate/article 140 duringthe coating process;

FIG. 4B is a side view of FIG. 4A illustrating a glass substrate 140resting on pins 136 that extend into the substrate carrier base 130 fora distance from the substrate carrier surface 130 a, a plurality ofmagnets 134 that extend from the surface 130 a of the substrate carrier130 and through the substrate for a distance beyond the base 130 b, aside stopper 150 extending from the base of carrier 130 to a distancefrom glass article 140's top face 140 a;

FIG. 5 schematically depicts one of the pins 138 a and 138 b againstwhich a glass substrate 140 is held by the force exerted against it by aspring loaded adjustable pin 138 a, and a shaped edge 141 that is incontact with the pin, in this case a chamfered edge;

FIG. 6 illustrates substrate carriers 130 attached to dome 110 such thatthe retractable pin 138A, is positioned perpendicular to the rotationdirection, that is, closer to opening at the top T of the dome 110 thanthe pins 138 b also illustrated in FIG. 6;

FIG. 7 a-c is a schematic representation of the fluorinated silanegrafting reaction with glass or an oxide AR coating;

FIG. 8 illustrates the AR optical coating layers that would underlie theETC coating to provide a barrier to isolate glass surface chemistry andcontamination, and further to provide a lower activation energy site forfluorinated silanes to chemically bond to the AR optical coating withmaximum coating density as well as crosslinking over the coated surfacein order to maximize abrasion reliability (durability);

FIG. 9 is an illustration of AR-ETC coated GRIN lenses 208 for use withoptical fibers 206 and some of their uses;

FIG. 10 is a comparison of abrasion testing data for a glass articlehaving a PVD 8-10 nm ETC on 6 layer ARC (Nb2O5/SiO2) coating and a glassarticle having only a spray coated ETC coating;

FIG. 11 is a comparison of the abrasion reliability of a glass articlehaving a 6 layer PVD IAD-EB AR coating and an 8-10 nm thermal depositedETC coating on top of the AR coating relative to a glass article havingPVD AR coating deposited in a first conventional coater and an ETCdeposited in a second conventional coater;

FIG. 12 is a graph of % Reflectance versus wavelength for glass articlescoated with an AR coating and an ETC coating after 6K, 7K, 8K and 9Kwipes;

FIG. 13 is a graph of % Transmission versus wavelength for glassarticles with an AR coating and an ETC coating after 6K, 7K, 8K and 9Kwipes;

FIG. 14 is a graph of Reflectance % versus wavelength and illustratingthe effect of the numbers of AR coating layers/periods reflectanceversus glass without an AR coating;

FIG. 15 illustrates an adjustable magnetic carrier 130 a that issubstantially similar to the carrier 130 illustrated in FIG. 4A andenables the use of a single carrier for different size substrates;

FIG. 16A illustrates a prior art dome carrier 300 having a plurality ofopenings 302 for placements of the lenses that are to be coated;

FIG. 16B illustrates a lens 304 that has slipped off one carrier 300shoulder 306 inside opening 302, the lens 304 being in a position to bebroken as the carrier 300 cools;

FIG. 17A is an illustration of an embodiment of the coating apparatushaving a shadow mask covering a selected area of the dome to improve theuniformity of the optical coating;

FIG. 17B is a graph of the Water Contact Angle versus Abrasion Cyclesillustrating the improvement that is obtained using the mask asillustrated in FIG. 17A;

FIG. 18 is a simulation of the reflectance (y-axis) as a function ofwavelength (x-axis) for a glass substrate coated with a 6 layer ARcoating (Nb₂O₅/SiO₂) and an ETC coating with the AR coating having athickness variation of 2%;

FIG. 19 graphically depicts the reflectance (y-axis) as a function ofwavelength for a plurality of actual samples coated with a 6 layer ARcoating (Nb₂O₅/SiO₂) and an ETC coating; and

FIG. 20 graphically depicts the glass article of one or more embodimentsincluding an optical coating and an ETC coating.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of glass articlescoated with optical coatings and easy-to-clean coatings and methods andapparatuses for forming the same, examples of which are illustrated inthe accompanying drawings. Whenever possible, the same referencenumerals will be used throughout the drawings to refer to the same orlike parts. One embodiment of a coating apparatus is schematicallydepicted in FIG. 1A. The coating apparatus generally includes a vacuumchamber with a magnetic dome positioned therein. The coating apparatusalso includes an e-beam source, a thermal evaporation source and aplasma source. Glass substrates to be coated can by magneticallyattached to an underside of the dome and coated with an optical coatingand an ETC coating using the e-beam source and the thermal evaporationsource, respectively. In embodiments, the plasma source may be used todensify the deposited optical coating materials. Various embodiments ofapparatuses and methods for sequentially applying optical coatings andETC coatings to glass substrates will be described in more detail hereinwith specific reference to the appended drawings.

Herein the terms “process” and “method” may be used interchangeably.Also herein the terms “shadowless” and “shadow free” mean that theoptical coating is uniformly deposited over the entire surface of theglass substrate such that, when the glass article with the coatingdeposited using the methods and apparatuses described herein is viewed,the shadow that is observed on glass articles having optical coatingprepared using conventional optical coating methods and apparatuses isnot observed. The shadow observed on conventionally coated glassarticles arises when areas of the substrate being coated shield thesurface of the substrate from the deposition of the optical coatingmaterials. These shadows are frequently observed adjacent to elementsthat are used to hold the substrate being coated in place during thecoating process or are on the substrate carrier for transport of thecarrier and the elements being coated into and out of the coater.

The terms “glass article” and “glass substrate” are used hereininterchangeably and generally refer to any glass item coated using themethods and apparatuses described herein.

The present disclosure is directed to a process in which both an opticalcoating, for example an AR coating, comprising alternating layers ofhigh refractive index and low refractive index materials, and an ETCcoating, for example a perfluoroalkylsilane coating, can be applied to aglass substrate in sequential steps (i.e., first applying the opticalcoating and then applying the ETC coating over the optical coating)using substantially the same procedure without exposing the article toair or ambient atmosphere at any time during the application of theoptical coating and the ETC coating. A reliable ETC coating provideslubrication to surface(s) of glass, transparent conductive coatings(TCC), and optical coatings. In addition, the abrasion resistance ofglass and optical coatings will be more than 10 times better than theconventional coating process or 100-1000 times better than an AR coatingwithout an ETC coating by using an in-situ, one-step process in whichthe coatings are sequentially applied, as graphically depicted in FIGS.10, 11, and 17B. Using such techniques, the ETC coating can beconsidered as part of the optical coating during design and, as such,the ETC coating will not change the desired optical performance. Theglass articles described herein are shadow free across the opticallycoated surface of the glass.

A particular example of an in-situ process is a box coater schematicallydepicted in FIG. 1A. The box coater is equipped with an electron beam(e-beam) source for optical coatings, a thermal evaporation source forthe ETC coating material, and an ion beam or a plasma source for surfacecleaning before coating and optical coating impaction during coating toincrease the density of the coating and the smoothness of the coatingsurface.

The optical coating is composed of high and median or low refractiveindex materials. Exemplary high index materials having an index ofrefraction n greater than or equal to 1.7 and less than or equal to 3.0include: ZrO₂, HfO₂, Ta₂O₅, Nb₂O₅, TiO₂, Y₂O₃, Si₃N₄, SrTiO₃, WO₃; anexemplary median index material having an index of refraction n greaterthan or equal to 1.5 and less than 1.7 is Al₂O₃; and an exemplary lowindex materials having an index of refraction n greater than or equal to1.3 and less than or equal to 1.6) include: SiO₂, MgF₂, YF₃, YbF₃. Theoptical coating stack that is deposited on a substrate comprises atleast one material/layer to provide a specified optical function. Inmost cases, a high and a low index material can be used to design acomplex optical filter (including AR coatings), for example, HfO₂ as thehigh index material and SiO₂ as the low index material. TCC(two-component coating) materials suitable for use in the coatingsinclude ITO (indium tin oxide), AZO (Al doped zinc oxide), IZO (Znstabilized indium oxides), In₂O₃, and similar binary and ternary oxidecompounds.

In embodiments, the optical coatings are applied to glass substratesusing PVD coating (sputtered or IAD-EB coated optical coating withthermal evaporation of the ETC coating). PVD is a “cold” process inwhich the substrate temperature is under 100° C. As a result there is nodegradation of the strength of a chemically strengthened or temperedglass substrate to which the coatings are applied.

In the embodiments described herein, the glass used to make the shadowfree, optical and ETC coated glass articles described herein may be anion-exchanged or non-ion-exchanged glass. Exemplary glasses includesilica glass, aluminosilicate glass, borosilicate glass,aluminoborosilicate glass and soda lime glass. The glass articles have athickness in the range of 0.2 mm to 1.5 mm, and a length and widthsuitable for the intended purpose. Thus the length and width of theglass article can range from that of a cell phone to tablet computer, orlarger.

The optical coatings referred to herein include antireflection coatings(AR coatings), band-pass filter coatings, edge neutral mirror coatingsand beam splitters, multi-layer high-reflectance coatings and edgefilters as described in H. Angus Macleod, “Thin Film Optical Filters”,3^(rd) edition, Institute of Physics Publishing. Bristol andPhiladelphia, 2001. Applications using such optical coatings includedisplays, camera lenses, telecommunications components, instruments,medical devices, photochromic and electrochromic devices, photovoltaicdevices, and other elements and devices.

Alternating layers of high and low refractive index materials can beused to form optical coatings, such as antireflective or anti-glare forultraviolet (“UV”), visible (“VIS”) and infrared (“IR”) applications.The optical coatings can be deposited using a variety of methods. Hereinthe PVD method (i.e., ion-assisted, e-beam deposition) for depositingthe optical coatings is used as an exemplary method. The opticalcoatings comprise at least one layer of a high index material H and atleast one layer of low index material L. Multilayer coatings consist ofa plurality of alternating high and low index layers, for example, HL,HL, HL . . . , etc., or LH, LH, LH . . . , etc. One pair of HL layers(or LH layers) is referred to as a “period” or a “coating period.” Amedium index material M can be used in place of a low index material inall or some of the low index layers. The term “index,” as used herein,refers to the index of refraction of the material. In a multilayercoating the number of periods can range widely depending on the functionof the intended product. For example, for AR coatings, the number ofperiods can be in the range of greater than or equal to 2 and less thanor equal to 20. An optional final capping layer of SiO₂ can also bedeposited on top of the AR coating as a final layer. Various techniquesmay be used to deposit the ETC material on top of the optical coatingwithout exposing the optical coating to the ambient atmosphereincluding, without limitation, thermal evaporation, chemical vapordeposition (CVD) or atomic layer deposition (ALD).

The optical coatings deposited on the glass substrates described hereinmay be multilayer optical coatings comprising at least one period of ahigh refractive index material and a low refractive index material. Thehigh refractive index material may be selected from ZrO₂, HfO₂, Ta₂O₅,Nb₂O₅, TiO₂, Y₂O₃, Si₃N₄, SrTiO3, and WO₃; however, it should beunderstood that other suitable high refractive index materials may beused. The low refractive index material may be selected from the groupconsisting of SiO₂, MgF₂, YF₃, and YbF₃; however, it should beunderstood that other suitable low refractive index materials may beused. In some embodiments, the low refractive index material may bereplaced with a medium refractive index material such as Al₂O₃ oranother suitable medium refractive index material.

In one embodiment, the present disclosure is directed to a process inwhich, in a first step, a multilayer optical coating is deposited on aglass substrate followed by a second step in which the ETC coating isthermally evaporated and deposited in the same chamber as the opticalcoating. In another embodiment a multilayer optical coating is depositedon a glass substrate in one chamber followed by the thermal evaporationand deposition of the ETC coating on top of the multilayer coating in asecond chamber, with the provision that the transfer of the multilayercoated substrate from the first chamber to the second chamber is carriedout inline in a manner such the substrate is not exposed to air betweenthe application of the multilayer coating and the ETC coating. Thecoating techniques utilized may include, without limitation PVD,CVD/PECVD, and ALD coating techniques. Depending on the size of thechamber or chambers and the size of the substrates being coated, one ora plurality of substrates can simultaneously be coated within a singlechamber.

The multilayer optical coatings are typically oxide coatings in whichthe high index coating is a lanthanide series oxide such as La, Nb, Y,Gd or other lanthanide metals, and the low index coating is SiO₂. TheETC materials may be, for example, fluorinated silanes, typically alkylperfluorocarbon silanes having the formula (R_(F))_(x)SiX_(4-x), whereR_(f) is a linear C₆-C₃₀ alkyl perfluorocarbon, X=Cl or —OCH₃— and x=2or 3. The fluorocarbons have a carbon chain length in the range ofgreater than or equal to 3 nm and less than or equal to 50 nm. Thefluorocarbons can be obtained commercially from vendors including,without limitation, Dow-Corning (for example fluorocarbons 2604 and2634), 3M Company (for example ECC-1000 and 4000). Daikin Corporation,Canon, Don (South Korea), Ceko (South Korea), Cotec-GmbH (for exampleDURALON UltraTec) and Evonik.

FIG. 1A schematically depicts a coating apparatus 100 and variousoperating elements of the apparatus according to one or more embodimentsdisclosed herein. Coordinate axes are provided for reference. In afrontal view x is from side-to-side (i.e., left to right), y is fromfront-to-back (i.e., in and out of the page) and z is frombottom-to-top. The coating apparatus 100 generally comprises a vacuumchamber 102 having therein a magnetic rotatable dome 110 with lip 161(depicted in FIG. 3A) that is part of a frame 160 (further illustratedin FIG. 3B) that supports dome 110. The dome includes a plurality ofsubstrate carriers 130 magnetically attached to an underside of the domeas illustrated in FIG. 2. A plasma source 118 is located in the vacuumchamber 102 below the dome 110 and is generally oriented to emit ions orplasma upwards, towards the underside of the dome 110. The plasma sourceis used to densify the optical coating materials as they are depositedand/or after deposition thereby increasing the hardness of the finishedoptical coating. Specifically, the ions or plasma emitted from theplasma source impact the coating during deposition and/or after acoating layer has been applied resulting in a densification of thedeposited material. Densifying the deposited optical coating improvesthe abrasion resistance of the optical coating. For example, in someembodiments, the deposited optical coating will have at least double theabrasion reliability or abrasion resistance of an optical coatingdeposited without the use of a plasma source.

The coating apparatus further comprises an e-beam source 120 locatedbelow the dome 110 and an e-beam reflector 122 for directing the e-beamfrom the e-beam source toward the optical coating material being appliedto the glass substrate to thereby vaporize the optical material. Ashadow mask 125 for enabling uniform coating across the dome is locatedbelow the dome 110. The shape and position of the shadow mask 125 areadjustable such that the shadow mask is “tunable” to achieve a desiredcoating uniformity. The shadow mask 125 is positioned on a support 125 asuch that the position of the shadow mask 125 can be adjusted verticallyalong the support 125 a, as indicated by the dashed double headed arrow.The position of the shadow mask 125 on the support 125 a can be adjustedas needed to prevent the shadow mask from shielding the glass substrateslocated on the underside of the dome 110 from the ions or plasma emittedfrom the plasma source 118 as the optical coating is applied. While FIG.1A depicts a single e-beam source 120, it should be understood that aplurality of e-beam sources can be used to minimize the time to changefrom one coating material to another, for example, changing from Nb₂O₅to SiO₂ and back again, as required to deposit the required number ofindividual layers of material for the optical coating. For example, insome embodiments, the coating apparatus may comprise greater than orequal to 2 e-beam sources and less than or equal to 6 e-beam sources.When a plurality of e-beam sources are used, each e-beam source may bedirected to a separate container (i.e., the boats 126, described furtherherein) holding the material to be coated.

The coating apparatus 100 further comprises an optical coating carrier124 having a plurality of boats 126 which contain the optical coatingmaterial. The boats 126 are separate source containers used to containthe different materials used to deposit the optical coating layer. Theoptical coating carrier 124 is positioned in the vacuum chamber 102 suchthat an e-beam emitted from the e-beam source 120 can be reflected bythe e-beam reflector 122 onto the optical coating material contained inthe boats 126, thereby vaporizing the optical coating material. Theboats 126 contain different optical coating materials so that only onetype of coating material (e.g., either a high refractive index, lowrefractive index, or medium refractive index material), is applied atone time. After the proper thickness of one coating material is reachedthe lid (not depicted) of the corresponding boat is closed and a lid toanother boat containing a different coating material to be applied isopened. In this manner the high refractive index material, lowrefractive index material, or medium refractive index material can beapplied in an alternating manner to form an optical coating materialhaving the desired optical properties.

The coating apparatus 100 also comprises at least one thermalevaporation source 128 for evaporating the ETC coating material tofacilitate depositing the coating material onto glass substratesretained on the underside of the dome 110. The at least one thermalevaporation source 128 is positioned in the vacuum chamber 102 below thedome 110.

Still referring to FIG. 1A, the dome 110 is made of a light weightmaterial that is magnetic or contains a magnetic material, for exampleand without limitation, aluminum containing iron or another suitablemagnetic material. The dome 110 can be rotated either clockwise orcounter-clockwise. At the top center of the dome is an opening 164(depicted in FIG. 3B) and a transparent glass plate 116 is placed on theunderside of the dome to cover the opening. The transparent glass plate116 may include an opening 116 a as depicted in the enlarged view of thetransparent glass plate 116 depicted in FIG. 1B. A quartz monitor 114 isreceived in and passes through the transparent glass plate 116. Anoptical fiber 112 is positioned above the transparent glass plate 116,as illustrated. The quartz monitor 114 controls the deposition rate ofthe optical materials by feedback to the e-beam power supply so that thedeposition rate of the coating material is kept substantially constant.The optical fiber 112 is positioned above the transparent glass plate116 to protect it from the deposition materials within the vacuumchamber 102. The optical fiber measures reflectance to determine whenthe deposition of each layer of the coating material should be stoppedbecause it has reached the targeted design thickness.

FIG. 1C is an enlargement of the circled area of the transparent glassplate 116 of FIG. 1A showing the relative orientations of the opticalfiber 112, the quartz monitor 114 and the transparent glass plate 116.The quartz monitor 114 is positioned in the middle of the transparentglass plate 116 and passes through the opening 116 a. The optical fiber112 is positioned to the side of the quartz monitor 114. Lighttransmitted from the optical fiber 112 passes through the transparentglass plate 116 and is reflected back as the surface of the transparentglass plate is coated. The arrows adjacent to % R schematically depictthe reflectance of light from the surface 116 b of the transparent glassplate as the transparent glass plate is being coated. The reflectanceincreases with the thickness of the coatings applied to surface 116 b ofthe transparent glass plate. The light reflected from the surface 116 bof the transparent glass plate is directed back to an optical sensor(not shown) coupled to a controller (not shown) of the e-beam source.The output of the optical sensor (which is indicative of the thicknessof the applied optical coating and/or the ETC coating) is utilized bythe controller to determine the deposited thickness of the coatings. Assuch, the reflected light can be used to control the deposited thicknessof an individual layer, a coating period, and the entire optical coatingas well as the deposited thickness of the ETC coating.

The top of the dome 110 is attached to a vacuum shielded rotation shaft117 indicated by the dashed parallel lines. The vacuum shielded rotationshaft 117 has a vacuum seal bearing 119 attached to the vacuum shieldedrotation shaft for rotating the vacuum shielded rotation shaft 117 anddome 110. Accordingly, it should be understood that the vacuum shieldedrotation shaft 117 is vacuum sealed to the top of the dome 110. Thevacuum shielded rotation shaft 117 is driven by an external motor (notillustrated) located external to the vacuum chamber 102. In anembodiment, the dome 110 may be rotated at a rotation frequency in therange from about 20 rpm to about 120 rpm. In another embodiment therotation frequency is in the range from about 40 rpm to about 83 rpm.

FIG. 2 schematically depicts a segment 110 a of dome 110. As shown inFIG. 2, a plurality of substrate carriers 130 are magnetically attachedto the dome 110. The substrate carriers 130 are utilized to secure glasssubstrates for coating in the coating apparatus 100.

FIG. 3A is a drawing illustrating an oblique bottom-up side view of asegment 110 a of the dome 110 showing the lip 161 with a plurality ofsubstrate carriers 130 magnetically attached to the dome 110. FIG. 3B isan illustration of the frame 160 that is used to support a plurality ofsegments 110 a. The frame 160 has an outer lip 161 (as depicted in FIG.3A), an inner rim (not numbered) adjacent to opening 164 to which thevacuum shielded rotation shaft 117 can be attached (not illustrated) anda plurality of spokes 162 extending radially outward from the inner rim.The spokes 162 are sufficiently wide to accommodate the side edges ofthe dome segments as is illustrated at 168.

FIG. 17A is a simplified illustration of an alternative embodiment of acoating apparatus for depositing an optical coating and an ETC coatingon a substrate. In this embodiment, the coating apparatus includes ashadow mask 127 covering a selected area of the dome to improve theuniformity of the optical coating deposited on the substrate. Thesupport for adjustably supporting the shadow mask 127 is not depicted inFIG. 17A. In the coating apparatus of FIG. 17A the plasma source is anion source 118 a. Since the ion source 118 a and the e-beam source 120used to evaporate the optical coating materials are located on differentsides of the vacuum chamber, the ion source is not shielded by theshadow mask, thereby improving the efficacy of the ion source 118 a inhardening the deposited optical coating materials. The ion source isused to densify the optical coating material to near bulk densitythereby increasing the hardness of the optical coating and improving theabrasion reliability/abrasion resistance of the optical coating.

Referring now to FIGS. 4A and 4B, a substrate carrier 130 made forcarrying a single size substrate is schematically depicted. Asillustrated in FIG. 4A, the substrate carrier 130 has a non-magneticsubstrate carrier base 131, a plurality of magnets 134 for magneticallyattaching the carrier to the dome 110 and for off-setting the substratecarrier a distance from the dome. The substrate carrier 130 alsoincludes a plurality of pins 136 for supporting a surface of a glasssubstrate 140 (illustrated in FIG. 4B) and a spring system 132. Thespring system 132 generally includes a retractable pin 138 a that isheld in place by a spring 133 (schematically depicted as an arrow) thatbiases the retractable pin 138 a in the direction indicated by thearrow, and a plurality of fixed pins 138 b. Pins 138 a and 138 b areused to hold a glass substrate 140 (indicated by dashed line) in placeon the substrate carrier 130 while the glass substrate is being coated.FIG. 4B is a side view of FIG. 4A illustrating a glass substrate 140supported on pins 136 that extend into the nonmagnetic substrate carrierbase 131 for a distance from the substrate carrier base surface 131 a, aplurality of magnets 134 that extend from the surface 131 a of thesubstrate carrier 130 and through the substrate for a distance beyondthe base 131 b, a side stopper 150 extending from of the nonmagneticsubstrate carrier base 131 to a distance from a top surface 140 a of theglass substrate 140. The side stopper 150 orients the glass substrate onthe nonmagnetic substrate carrier base 131 without affecting theapplication of the coatings thereby preventing “shadows” on the surfaceof the glass substrate. Specifically, the top surface 140 a of the glasssubstrate is the surface that will be coated with the optical coatingand the easy-to-clean coating. For a glass substrate having a thicknessof 5 mm, the top of side stopper 150 will be in the range of 2-3 mmbelow the top surface 140 a of the glass substrate 140. The opening (notnumbered) in the middle of the substrate carrier reduces the weight ofthe carrier.

Referring now to FIG. 15, an adjustable substrate carrier 130 a similarto the fixed substrate carrier 130 illustrated in FIG. 4A is depicted.The adjustable substrate carrier 130 a has a non-magnetic substratecarrier base 131 which includes a plurality of magnets 134 for attachingthe adjustable substrate carrier to the dome of the coating apparatus asdescribed above. The adjustable substrate carrier 130 a also includes aplurality of pins 136 extending from the surface of the substratecarrier for supporting a surface of a glass substrate positioned on theadjustable substrate carrier 130 a. A housing 138 aa is positionedproximate an edge of the adjustable substrate carrier 130 a and houses aretractable pin 138 a (depicted partially extended from the housing).The housing 138 aa includes a spring (not shown) positioned in thehousing 138 aa. The spring bias the retractable pin 138 a outward fromthe housing 138 aa. The adjustable substrate carrier 130 a mayoptionally include side stoppers 150 a (not illustrated in FIG. 15) fororienting a glass substrate on the adjustable substrate carrier 130 a.In the embodiment depicted in FIG. 15, the adjustable substrate carrier130 a further includes a plurality of moveable pins 139 for holding anedge of the glass substrate. The moveable pins 139 are positioned intracks 137 to facilitate adjustably positioning the moveable pins 139relative to the adjustable substrate carrier 130 a. The moveable pins139, in combination with the retractable pin 138 a enable the use of asingle carrier for different size substrates. The substrate orsubstrates may be held by the pins, and any optional side stoppers 150 ain the same manner as described above with respect to FIG. 4A so that ashadow free coating is formed on the substrate.

As indicated in the foregoing paragraph, the substrate carriers 130, 130a have a non-magnetic substrate carrier base 131 and a plurality ofmagnets 134 for holding the carrier to the dome 110 and for off-settingthe carrier a distance from the dome. The use of these magnetic carriersis an improvement over dome carriers that are used in the coating ofoptical elements such as lenses. For example, FIG. 16A illustrates aconventional dome carrier 300 having a plurality of openings 302 forpositioning lenses that are to be coated. When the lenses are coatedthey are inserted into an opening in the carrier. However in thisconventional design it is difficult to uniformly coat both the insideand outside of the dome. It is also difficult to keep the coatingmaterial away from surfaces of the lenses that are not to be coated. Inaddition, the part being coated can move with respect to the opening inthe dome as the dome heats up, resulting in breakage as the dome coolsafter coating. For example, FIG. 16B illustrates a lens 304 that hasslipped off one support shoulder 306 inside an opening 302 of the domecarrier. As is easily seen, if the carrier cools faster than the lens304, the contraction of the carrier can cause the lens to break. In thepresent application, since the substrate carrier is off-set a distancefrom the dome by the magnets that hold the carrier to the dome, heattransfer is minimized and breakage does not occur as the dome cools. Inaddition, only one side of the glass article being coated is subjectedto the coating materials due to the proximity of the carrier/substratecombination to interior surface of the dome. As a result thedifficulties mentioned above in conventional dome carriers can beavoided.

Referring now to FIG. 5, a cross section of the pins 138 a and 138 bagainst which a glass substrate is held by the force exerted against itby the retractable pin 138 a is schematically depicted. The glasssubstrate has a shaped edge which fits between the head 138 h of pins138 a and 138 b and the remainder of the body of the pin. The edge ofthe glass substrate may be chamfered as illustrated at 141, rounded,bull nosed or otherwise contoured. When the glass substrate 140 isengaged with the pins 138 a, 138 b, the top 140 a of the glass substrateis 2-3 mm below the top of the pin 138 a or 138 b. In this figure,reference numeral 140 b indicates the bottom surface of glass substrate140.

Referring now to FIG. 4A and FIG. 6, a glass substrate 140 is loadedonto the substrate carrier 130 and the combination of the glasssubstrate 140 and the substrate carrier 130 is magnetically attached tothe underside of dome 110. When the substrate carrier 130 with glasssubstrate 140 (dashed line) is loaded onto the dome 110 for coating, theretractable pin 138 a is positioned perpendicular to the rotationdirection of the dome 110 as indicated by the arrow; that is, the pin iscloser to the opening at the top T of the dome 110 than the fixed pins138 b. When the substrate carrier is so positioned the optical coatingis uniformly deposited over the entire surface of the glass substrate140 to form a “shadowless” or “shadow free” coated glass substrate 140.These terms, “shadowless” and “shadow free,” refer to the fact that if:

-   -   (1) the retractable pin 138 a is not positioned on dome 110 as        described and illustrated in FIG. 6, and    -   (2) the top surface 140 a of glass substrate 140 is less than 1        mm below head 138 h of pin 138 a, and    -   (3) the top of side stoppers 150 are not lower than the top        surface 140 a;        then the deposition of the optical coating will be non-uniform        in the areas where these elements and other elements holding the        substrate are located. As a result, the optical coating will be        thinner near these elements and thicker as one moves away from        them. The result is a non-uniform optical deposition or “shadow”        that can be noticed by a user of the articles. Such shadows can        be avoided using the apparatus and methods described in this        disclosure.

Referring again to FIG. 1A, once the adjustable substrate carrier 130 ais magnetically attached to the dome 110, the materials for applying theoptical coating to the glass substrate are loaded into separate boats126 (i.e., separate source containers) of the optical coating carrier124. As noted hereinabove, the optical coating is composed ofalternating layers of high and low refractive index materials oralternating layers of high and middle refractive index materials.Exemplary high index materials having an index of refraction n greaterthan or equal to 1.7 and less than or equal to 3.0 are: ZrO₂, HfO₂,Ta₂O₅, Nb₂O₅, TiO₂, Y₂O₃, Si₃N₄, SrTiO₃, WO₃; an exemplary medium indexmaterial having an index of refraction n greater than or equal to 1.5and less than 1.7 is Al₂O₃; and an exemplary low index materials havingan index of refraction n greater than or equal to 1.3 and less than orequal to 1.6) are: SiO₂, MgF₂, YF₃, YbF₃. In some embodiments, mediumrefractive index material may be used to form the low refractive indexlayer L. Accordingly, in some embodiments, the low index material may beselected from SiO₂, MgF₂, YF₃, YbF₃ and Al₂O₃. In an exemplaryembodiment, the optical coating materials are oxide coatings in whichthe high index coating is a lanthanide series oxide such as La, Nb, Y,Gd or other lanthanide metals, and the low index coating is SiO₂. Inaddition, the material for applying the easy-to-clean (ETC) coating isloaded in to the at least one thermal evaporation source 128. As notedhereinabove the ETC materials may be, for example, fluorinated silanes,typically alkyl perfluorocarbon silanes having the formula(R_(F))—SiX_(4-x), where R_(f) is a linear C₆-C₃₀ alkyl perfluorocarbon,X=Cl or —OCH₃— and x=2 or 3. The fluorocarbons have a carbon chainlength in the range of greater than or equal to 3 nm and less than orequal to 50 nm.

Once the coating materials are loaded, the vacuum chamber 102 is sealedand evacuated to a pressure less than or equal to 10⁻⁴ Torr. The dome110 is then rotated in the vacuum chamber by rotating the vacuumshielded rotation shaft 117. The plasma source 118 is then activated todirect ions and/or plasma towards the glass substrates positioned on theunderside of the dome 110 to densify the optical coating materials asthey are applied to the glass substrate. Thereafter the optical coatingand ETC coating are sequentially applied to the glass substrate. Theoptical coating is first applied by vaporizing the optical materialspositioned in the boats 126 of the optical coating carrier 124.Specifically, the e-beam source 120 is energized and emits a stream ofelectrons which are directed onto the boats 126 of the optical coatingcarrier 124 by the e-beam reflector 122. The vaporized material isdeposited on the surface of the glass substrates as the glass substratesare rotated with the dome 110. The rotation of the dome 110, inconjunction with the shadow mask 125 and the orientation of the glasssubstrates on the substrate carriers 130, allows the optical coatingmaterials to be uniformly coated onto the glass substrate carriers,thereby avoiding “shadows” on the coated surface of the glass substrate.As described hereinabove, the e-beam source 120 is utilized tosequentially deposit layers of high refractive index material and lowrefractive index material or medium refractive index material to achievean optical coating having the desired optical properties. The quartzmonitor 114 and the optical fiber 112 are utilized to monitor thethicknesses of the deposited materials and thereby control thedeposition of the optical coating, as described herein.

Once the optical coating has been applied to the glass substrate to thedesired thickness using the desired coating material(s), optical coatingceases and the ETC coating is applied over the optical coating bythermal evaporation as the glass substrate rotates with the dome 110.Specifically, the ETC material positioned in the at least one thermalevaporation source 128 is heated, thereby vaporizing the ETC material inthe vacuum chamber 102. The vaporized ETC material is deposited on theglass substrate by condensation. The rotation of the dome 110 inconjunction with the orientation of the glass substrates on thesubstrate carriers 130 facilitates uniformly coating the ETC materialsonto the glass substrate. The quartz monitor 114 and the optical fiber112 are utilized to monitor the thicknesses of the deposited materialsand thereby control the deposition of the ETC coating, as describedherein.

FIGS. 7 (a)-(c) are a schematic representation of the fluorinated silanegrafting reactions with glass or an oxide optical coating (i.e., thereaction between the ETC coating material and the glass or an oxideoptical coating). FIG. 7 c illustrates that, when fluorocarbontrichlorosilane is grafted to the glass, the silane silicon atom can beeither (1) triply bonded (three Si—O bonds) to the glass substrate orthe surface of a multilayer oxide coating on the substrate or (2) doublybonded to a glass substrate and have one Si—O—Si bond to an adjacentR_(F)Si moiety. The ETC coating process time is very short and can beused to provide an ETC coating having a thickness in a range fromgreater than or equal to 3 nm and less than or equal to 50 nm over thefreshly applied optical coating without breaking vacuum (i.e., withoutexposing the optical coating to ambient atmosphere). In the coatingprocess described herein the ETC material is evaporated from a singlesource. However it should be understood that the ETC material may alsobe simultaneously evaporated from a plurality of sources. For example,it has been found that 2-5 separate ETC material sources may beadvantageous. Specifically, the use of a plurality of sources containingthe ETC material results in a more uniform ETC coating and can enhancecoating durability. The term “sources” as used herein, refers to thecontainers or crucibles from which the ETC material is thermallyevaporated.

In the embodiments described herein, an SiO₂ layer is generally appliedas a capping layer for optical coatings. The SiO₂ layer is generallydeposited as part of the optical coating prior to the deposition of theETC coating. This SiO₂ layer provides a dense surface for grafting andcrosslinking of silicon atoms of the ETC coating as these layers weredeposited at high vacuum (10⁻⁴-10⁻⁶ Torr) without the presence of freeOH. Free OH, for example a thin layer of water on the glass or ARsurface, is detrimental during ETC material deposition because the OHprevents the silicon atoms in the ETC material from bonding with theoxygen atoms of metal oxide or silicon oxide surfaces, that is, theoptical coating surface. When the vacuum in the deposition apparatus isbroken, that is, the apparatus is opened to the atmosphere, air from theenvironment, which contains water vapor, is admitted and the siliconatoms of the ETC coating react with the optical coating surface tocreate at least one chemical bond between the ETC silicon atom andsurface oxygen atom, and release alcohol or acid once exposed to air.Since the ETC coating material typically contains 1-2 fluorinated groupsand 2-3 reactive groups such as CH₃O— groups, the ETC coating is capableof bonding to 2-3 oxygen atoms at the optical coating surface, orcrosslinking with another coating molecule as shown in FIG. 7( c), tocreate a strongly bonded ETC coating. The PVD deposited SiO₂ surface ispristine and has a reactive surface. For example, for a PVD depositedSiO₂ cap layer, the binding reaction has a much lower activation energy,as is illustrated in FIG. 8, than on a glass that has a complicatedsurface chemistry, has an environmental contaminant on it or, has awater layer on the glass surface.

Thus, once the ETC coating has been applied over the optical coating,the glass substrate with the optical coating and the ETC coating isremoved from the chamber and allowed to cure in air. If allowed to curesimply by sitting at room temperature. (approximately 18-25° C.,Relative Humidity (RH) 40%) the curing will take 1-3 days. Elevatedtemperatures may be utilized to expedite curing. For example, in oneembodiment, the ETC coated article may be heated to a temperature of80-100° C. for a time period from about 10 minutes to about 30 minutesat a RH in the range of greater than 50% and less than 100%. Typicallythe relative humidity is in the range of 50-85%.

Once the ETC coating has been cured, the surface of the coating is wipedwith a soft brush or an isopropyl alcohol wipe to remove any ETCmaterial that has not bonded to the optical coating.

The methods and apparatuses described herein may be used to producedcoated glass articles 300, such as coated glass substrates 310, whichhave both an optical coating 320 (such as an AR coating or a similaroptically functional coating) and an ETC coating 330 positioned over theoptical coating, as shown in FIG. 20. Utilizing the methods andapparatuses described herein, the coated glass articles 300 aregenerally shadow free across the optically coated surface of the glassarticle, as shown in FIG. 20. In embodiments such as the embodimentshown in FIG. 20, the optical coating 320 applied to the glass articlemay have a plurality of periods 340 consisting of a layer of highrefractive index material H 350 having an index of refraction n greaterthan or equal to 1.7 and less than or equal to 3.0, and a layer of lowrefractive index material L 360 having an index of refraction n greaterthan or equal to 1.3 and less than or equal to 1.6. The layer of highrefractive index material 350 may be the first layer of each period andthe layer of low refractive index material L 360 may be the second layerof each period. Alternatively, the layer of low refractive indexmaterial may be the first layer of each period and the layer of highrefractive index material H may be the second layer of each period. Insome embodiments, the number of coating periods in the optical coatingmay be greater than or equal to 2 and less than or equal to 1000. Theoptical coating 320 may further include a capping layer of SiO₂ 370. Thecapping layer 370 may be applied on over one or a plurality of periods340 and may have a thickness in the range greater than or equal to 20 nmand less than or equal to 200 nm. In the embodiments described herein,the optical coating may have a thickness in the range from greater thanor equal to 100 nm to less than or equal to 2000 nm. However, greaterthicknesses are possible depending on the intended use of the coatedarticle. For example, in some embodiments, the optical coating thicknesscan be in the range of 100 nm to 2000 nm. In some other embodiments, theoptical coating thickness can be in the range of 400 nm to 1200 nm oreven in the range from 400 nm to 1500 nm.

The thickness of each of the layers of high refractive index materialand low refractive index material may be in a range from greater than orequal to 5 nm and less than or equal to 200 nm. The thickness of each ofthe layers of high refractive index material and low refractive indexmaterial may be in a range from greater than or equal to 5 nm and lessthan or equal to 100 nm. As will be described further herein, the coatedglass articles exhibit an improved resistance to abrasion to thespecific coating methods and techniques utilized herein. The degradationof the coatings applied to the glass article may be assessed by thewater contact angle following exposure of the glass coating to abrasiontesting. The abrasion testing was carried out by rubbing grade 0000#steel wool across the coated surface of the glass substrate under a 10kg normal load. The abraded area is 10 mm×10 mm. The frequency ofabrasion is 60 Hz and the travel distance of the steel wool is 50 mm.The abrasion testing is performed at a relative humidity RH<40%. In theembodiments described herein, glass articles have a water contact angleof at least 75° after 6,000 abrasion cycles. In some embodiments, theglass articles have a water contact angle of at least 105° after 6,000abrasion cycles. In still other embodiments, the glass articles have awater contact angle of greater than 90° after 10,600 abrasion cycles.

The resistance of the glass article to abrasion and degradation may alsobe assessed by the length of scratches present on the glass articlefollowing abrasion testing. In embodiments described herein, the coatedglass articles have a surface scratch length of less than 2 mm following8000 abrasion cycles.

Moreover, the resistance of the glass article to abrasion anddegradation may also be assessed by the change in the reflectance and/ortransmittance of the glass article following abrasion testing, as willbe described in more detail herein. In some embodiments, a % Reflectanceof the glass article after at least 8,000 abrasion/wiping cycles issubstantially the same as the % Reflectance of an unabraded/unwipedglass article. In some embodiments, the % Transmission of the glassarticle after at least 8,000 abrasion/wiping cycles is substantially thesame as the % Transmission of an unabraded/unwiped glass article.

The deposition methods described herein may be used to produce a shadowfree optical coating. This means that mean that the optical coating isuniformly deposited over the entire coated surface of the glasssubstrate. In embodiments of the coated glass substrates describedherein, the variation in a thickness of the optical coating from a firstedge of the optical coating to second edge of the optical coating of theglass substrate is less than 4%. For example, in some embodiments, thevariation the thickness of the optical coating from a first edge of theoptical coating to second edge of the optical coating of the glasssubstrate is less than or equal to 3%. In some other embodiments thevariation in the thickness of the optical coating from a first edge ofthe optical coating to second edge of the optical coating of the glasssubstrate is less than or equal to 2%. In still other embodiments, thevariation in the thickness of the optical coating from a first edge ofthe optical coating to second edge of the optical coating of the glasssubstrate is less than or equal to 1%.

Ion-assisted electron-beam deposition provides a unique advantage forcoating small and medium size glass substrates, for example those havingfacial dimensions in the range of approximately 40 mm×60 mm toapproximately 180 mm×320 mm, depending on chamber size. Ion assistedcoating process provides a freshly deposited optical coating on theglass surface that has low surface activation energy with regard to thesubsequent application of the ETC coating since there is no surfacecontamination (water or other environmental) that might impact ETCcoating performance and reliability. The application of the ETC coatingdirectly after completion of the optical coating improves crosslinkingbetween two fluorocarbon functional groups, improves wear resistance,and improves contact angle performance (higher oleophobic andhydrophobic contact angles) following thousands of abrasion cyclesapplied to the coating. In addition, ion-assisted e-beam coating greatlyreduces coating cycle time to enhance coater utilization and throughput.Further, no post deposition heat treatment or UV curing of the ETCcoating is required due to lower activation energy of the opticalcoating surface which makes the process compatible with post ETCprocesses in which heating is not permitted. Using the Ion-assistede-beam PVD processes described herein, the ETC material can be coated onselected regions to avoid contamination to other locations of substrate.

Example 1

A 4-layer SiO₂/Nb₂O₅/SiO₂/Nb₂O₅/ substrate AR optical coating wasdeposited on sixty (60) pieces of Gorilla™ Glass (commercially availablefrom Corning Incorporated) with dimension (Length, Width, Thickness) ofapproximately 115 mm L×60 mm W×0.7 mm T The coating was deposited usingthe methods described herein. The AR coating had a thickness ofapproximately 600 nm. After deposition of the AR coating an ETC coatingwas applied on top of the AR coating by thermal evaporation usingperfluoroalkyl trichlorosilanes having a carbon chain length in therange of 5 nm to 20 nm (Optool™ fluoro coating, Daikin Industries wasused as an exemplary species). The deposition of the AR and ETC coatingwas carried out in a single chamber coating apparatus as illustrated inFIG. 1A. After the AR coating was deposited the AR coating sourcematerial was shut off and the ETC material was thermally evaporated anddeposited on the AR coated glass. The coating process was 73 minutesincluding parts loading/unloading. Subsequently, after the ETC coatingwas cured, water contact angles were determined after the surface wasabraded using various abrasion cycles as indicated in Table 1. Theabrasion testing was conducted with #0 steel wool and a 1 kg weightload. The data in Table 1 indicates that the sample has very good wearand hydrophobic properties. The coating order and layer thickness for a6-layer Nb₂O₅/SiO₂ coating on a glass substrate is given in Table 2.

TABLE 1 Water contact angle abrasion test results Sample Before Abrasion3.5K Abrasion 4.5K Abrasion 5.5K Abrasion 1 113.8 114.2 116.1 109.9107.2 108.5 92.6 103.4 96.3 69.5 85.5 70.5

TABLE 2 Layer Number Material Thickness Range, nm 6 SiO₂ 80-120 5 Nb₂O₅75-90 4 SiO₂  5-20 3 Nb₂O₅ 40-80 2 SiO₂ 24-40 1 Nb₂O₅ 10-20 SubstrateGlass NA

Example 2

In this Example the same fluoro-coating used in Example 1 was coated ona GRIN-lens for optical connectors, as is illustrated in FIG. 9, for useon optical fibers 206 used in laptop computers. Numeral 200 and arrowpoint to of a selective region of the GRIN lenses 208 for placing an ETCcoating on top of an 850 nm AR coating to provide particle and wearresistance. Numeral 202 illustrates connecting an optical fiber to alaptop or tablet device, and numeral 204 illustrates the use of a coatedfiber optic to connect a laptop to a media dock.

FIG. 10 is abrasion testing data on a glass article having an 8-10 nmthermally deposited on a ETC coating on a 6 layer AR coating consistingof substrate/(Nb2O5/SiO2)3, ETC/6L-AR coating, versus a glass samplewith only the spray coated ETC coating. The glass was 0.7 mm thickCorning code 2319 glass which is commercially available, chemicallytempered (ion-exchanged) glass. The abrasion testing was carried outunder following conditions: grade 0000# steel wool, 10 kg load on 10mm×10 mm area, 60 Hz, 50 mm travel distance, RH<40%. A water contactangle greater than 75 degrees is the criterion for judging coatingfailure. It was found that glass having an AR coating without the ETCcoating was scratch damaged after only 10-20 wiping cycles. FIG. 10shows that both glass samples start out with a water contact angle of120°, and, after 6000 abrasion cycles the glass sample with only the ETCcoating had a water contact angle of 80° whereas the glass sample madeas described herein, ETC/6 layer-AR coating, had a water contact angleof at least 105°. After 10,000 abrasion cycles the water contact angleof the ETC/6 layer-AR coating coated article was greater than 90°. Thetest clearly indicates that a glass article having an ETC coatingdeposited on top of an AR coating has a much greater degree of scratchresistance than a glass article have only an ETC coating applied to theglass.

FIG. 11 is a comparison of the abrasion durability of a (1) a glassarticle with a 6 layer PVD IAD-EB AR coating and an 8-10 nm thermallydeposited ETC coating on top of the AR coating (indicated by numeral 220and the diamond data marker), versus a commercially available glassarticle (indicated by numeral 222 and the square data marker) having aPVD-AR coating deposited by a first commercial coater apparatus and anETC deposited in a second chamber by a commercial process such asdipping or spraying. Both coatings were deposited on samples of the samechemically tempered (ion-exchanged) 0.7 mm thick Corning Code 2319glass. Glass article 220 was coated according to the methods describedherein. The commercially available glass article was coated by acommercial coating vendor. The abrasion durability was carried out at arelative humidity of 40%. At the point indicated by arrow 224, onlyshort, shallow scratches, less than 2 mm long, appeared after 8,000cycles. In contrast, at the point indicated by arrow 226 deep, longscratches, greater than 5 mm long, appeared after only 200 wipes. Thetest results indicate that the abrasion durability of AR coating-ETCglasses coated as described herein is at least 10 times greater than thedurability of commercially available products.

FIG. 17B graphically depicts the Water Contact Angle versus AbrasionCycles illustrating the improvement that is obtained using a coatingapparatus configured as depicted in FIG. 17A. The water contact angleresults can be compared to those of FIGS. 10 and 11. The data in FIG.17B show that, after 10,000 abrasion cycles, all the substratesillustrated in FIG. 17B have a water contact angle of greater than 110°,and substantially all of the substrates had a water contact angle of112° or higher. In contrast, the data of FIGS. 10 and 11 indicate thatthe water contact angles were less than 100° after 10,000 abrasioncycles. Further, the data in FIG. 17B indicates that for substrates thathave been subjected to 12,000 abrasion cycles, the water contact anglesof the substrates is greater than 106°.

FIG. 12 is a graph of % Reflectance versus wavelength, where Reflectancemeans the percentage of light reflected from the surface of the coatedglass article coated with an AR coating and ETC coating as describedherein. A new (unabraded or unwiped) article was used for each wipingtest. The abrasion/wiping was carried out under following conditions:grade 0000# steel wool, 10 kg load on 10 mm×10 mm area, 60 Hz, 50 mmtravel distance, RH<40%. Reflectance was measured after 6K, 7K, 8K and9K abrasions. The graph indicates that new articles and articles wipedup to 8K wipes have substantially the same reflectance. After 8K wipesthe reflectance increases. This reflection increase is believed due toslight abrasion of the glass surface as a result of a large number ofwipes. In the graph the letter “A” means “After Wiping” and the letter“B” means “Before Wiping” (zero wipes). The letter “K” means “kilo” or“thousand”.

FIG. 13 is a graph of % Transmission versus wavelength. The testing wasperformed on coated glass articles coated with an AR coating and ETCcoating as described herein. A new (unabraded or unwiped) article wasused for each wiping test. The transmission test used the same articlesas the reflectance test. The graph indicates that new articles andarticles wiped up to 8K wipes have substantially similar transmissions,the transmission being the range of 95-96%. After 8K wipes thetransmission falls to approximate 92% over the entire wavelength range,as indicated by letter “C” in the graph of FIG. 13. This transmissiondecrease is believed due to slight abrasion of the glass surface as aresult of a large number of wipes. In the graph the letter “A” means“After wiping” and the letter “B” means “Before wiping” (zero wipes).The letter “K” means “kilo” or “thousand”

The data in FIGS. 12 and 13 indicate that the optical coating on theglass articles is highly durable in addition to having excellent watercontact angle retention as is shown by FIGS. 10 and 11.

FIG. 14 is a graph of Reflectance % versus wavelength illustrating theeffect of the numbers of AR coating layers/periods on reflectancerelative to glass without an AR coating. Curve 240 represents uncoatedion-exchanged glass, Corning Code 2319. Curve 244 is a 2-layer, or1-period, coating consisting of SiO₂/Nb₂O₃. Curves 246 and 248 are4-layer (2 periods) and 6-layer (3 periods) coatings consisting ofSiO₂/Nb₂O₃ layer pairs. Curve 242 is a 1-layer coating of Nb₂O₃. Thedata indicates that increasing the AR coating stack number(layers/periods) will broaden the utility of the AR coating spectralrange and will also decrease the Reflectance %.

Example 3

FIG. 18 is a computer simulation of the reflectance (y-axis) as afunction of wavelength (x-axis) for a glass substrates coated with a 6layer AR coating (Nb₂O₅/SiO₂) and an ETC coating. The AR coating wassimulated with a thickness variation of 2%. Accordingly, the resultantreflectance profile simulates the reflectance of a 6 layer AR coating(Nb₂O₅/SiO₂) and an ETC coating where the ETC coating has a thicknessvariation of 2%. FIG. 19 graphically depicts the reflectance (y-axis) asa function of wavelength for a plurality of actual samples coated with a6 layer AR coating (Nb₂O₅/SiO₂) and an ETC coating using the methods andapparatuses described herein. As depicted in FIG. 19, the reflectanceprofile of the actual samples is similar to the reflectance profile ofthe simulated samples, thus indicating that the samples coated using themethods described have an optical coating in which the thicknessvariation of the optical coating across the coated substrate (i.e., fromthe first edge to second edge of the optical coating) is less than 3%.

The AR/ETC coating described herein can be utilized in many commercialarticles. For example, the resulting coating can be used to maketelevisions, cell phones, electronic tablets, and book readers and otherdevices readable in sunlight. The AR/EC coatings also have utility inantireflection beamsplitters, prisms, mirrors and laser products;optical fibers and components for telecommunication; optical coatingsfor use in biological and medical applications; and for anti-microbialsurfaces.

In a first aspect, the disclosure provides a method for making a glassarticle having an optical coating and an easy-to-clean (ETC) coating ontop of the optical coating. The method includes: providing a coatingapparatus having a vacuum chamber for deposition of an optical coatingand an ETC coating; providing a magnetic rotatable dome within saidvacuum chamber for magnetically positioning a magnetic substrate carrierfor receiving a glass substrate thereon that is to be coated; providingwithin said vacuum chamber source materials for the optical coating andsource materials for the ETC coating; loading the glass substrate on themagnetic substrate carrier and magnetically attaching the magneticsubstrate carrier having the glass substrate thereon to the magneticrotatable dome; evacuating the vacuum chamber; rotating the magneticrotatable dome and depositing an optical coating on the glass substrate;rotating the magnetic rotatable dome and depositing the ETC coating ontop of the optical coating following deposition of the optical coating,wherein the optical coating is not exposed to ambient atmosphere priorto the deposition of the ETC coating; and removing the glass substratehaving the optical coating and the ETC coating from the vacuum chamberto obtain a glass substrate having a shadow-free optical coatingdeposited on the glass substrate and the ETC coating deposited on theoptical coating.

In a second aspect, the disclosure provides the method of the firstaspect further comprising curing the ETC coating.

In a third aspect, the disclosure provides the method according toeither of the first or second aspects wherein the ETC coating is curedin air at room temperature.

In a fourth aspect, the disclosure provides the method according toeither of the first or second aspects, wherein the ETC coating is curedby heating the ETC coating.

In a fifth aspect, the disclosure provides the method according to anyof the first through fourth aspects, wherein the vacuum chamber isevacuated to a pressure of less than or equal to 10⁻⁴ Torr.

In a sixth aspect, the disclosure provides the method according to anyof the first through fifth aspects, wherein the method further comprisesdensifying the optical coating as the optical coating is deposited.

In a seventh aspect, the disclosure provides the method according to anyof the first through sixth aspects, wherein the vacuum chamber containsat least one e-beam source for vaporizing the source materials for theoptical coating.

In an eighth aspect, the disclosure provides the method according to theseventh aspect, wherein the at least one e-beam source comprises greaterthan or equal to 2 and less than or equal to 6 e-beam sources and ane-beam from each source is directed to a separate container holding amaterial being coated.

In a ninth aspect, the disclosure provides the method according to anyof the first through eighth aspects, wherein the magnetic substratecarrier is selected from the group consisting of a fixed magneticsubstrate carrier and an adjustable magnetic substrate carrier.

In a tenth aspect, the disclosure provides the method according to anyof the first through ninth aspects, wherein depositing the opticalcoating comprises depositing a multilayer optical coating comprising atleast one period of a high refractive index material and a lowrefractive index material, wherein: the high refractive index materialis selected from the group consisting of ZrO₂, HfO₂, Ta₂O₅, Nb₂O₅, TiO₂,Y₂O₃, Si₃N₄, SrTiO₃, WO₃; and the low refractive index material isselected from the group consisting of SiO₂, MgF₂, YF₃, YbF₃ and Al₂O₃.

In an eleventh aspect, the disclosure provides the method according toany of the first through tenth aspects, wherein the glass substrate isformed from ion-exchanged silica glass, non-ion-exchanged silica glass,aluminosilicate glass, borosilicate glass, aluminoborosilicate glass, orsoda lime glass.

In a twelfth aspect, the disclosure provides the method according to anyof the first through eleventh aspects, wherein the source material forthe ETC coating is a alkyl perfluorocarbon silane of formula(R_(F))_(x)SiX_(4-x), where R_(F) is a linear C₆-C₃₀ alkylperfluorocarbon, X=Cl or —OCH₃— and x=2 or 3.

In a thirteenth aspect, the disclosure provides a magnetic substratecarrier for holding a substrate during a coating process. The magneticsubstrate carrier comprises a non-magnetic substrate carrier base; aplurality of magnets attached to the non-magnetic substrate carrierbase; a plurality of pins for supporting a surface of a glass substratepositioned on the magnetic substrate carrier; a spring system comprisinga retractable pin held in place by a spring that retracts theretractable pin, the retractable pin being extendable in a directionopposite the spring, a plurality of fixed pins, and a plurality of sidestoppers extending from the non-magnetic substrate carrier base for adistance such that, when the glass substrate is positioned on theplurality of pins, tops of the plurality of side stoppers are below atop surface of the glass substrate.

In a fourteenth aspect, the disclosure provides a magnetic substratecarrier for holding substrates during a coating process. The magneticsubstrate carrier comprises: a non-magnetic carrier base; a plurality ofmagnets attached to the non-magnetic carrier base; a plurality of pinsfor supporting a surface of a glass substrate; a housing with aretractable pin disposed in the housing, wherein the retractable pin isheld in place by a spring, the retractable pin being outwardly biasedfrom the housing; optional stoppers; and a plurality of movable pins forholding an edge of a glass substrate.

In a fifteenth aspect, the disclosure provides a glass articlecomprising an optical coating and an easy-to-clean coating on top of theoptical coating, the glass article being shadow free across an opticallycoated surface of the glass article, wherein: the optical coatingcomprises a plurality of periods consisting of a layer of highrefractive index material H having an index of refraction n greater thanor equal to 1.7 and less than or equal to 3.0, and a layer of lowrefractive index material L having an index of refraction n greater thanor equal to 1.3 and less than or equal to 1.6, the layer of highrefractive index material H being a first layer of each period and thelayer of low refractive index material L being a second layer of eachperiod; and an SiO₂ capping layer having a thickness in a range greaterthan or equal to 20 nm and less than or equal to 200 nm applied on topof the plurality of periods.

In a sixteenth aspect, the disclosure provides the glass article of thefifteenth aspect, wherein a number of coating periods is in a range fromgreater than or equal to 2 and less than or equal to 1000.

In a seventeenth aspect, the disclosure provides the glass article ofany of the fifteenth through sixteenth aspects, wherein the opticalcoating has a thickness in a range from greater than or equal to 100 nmto less than or equal to 2000 nm.

In an eighteenth aspect, the disclosure provides the glass article ofany of the fifteenth through seventeenth aspects, wherein a number ofcoating periods is in a range from greater than or equal to 2 and lessthan or equal to 20, and a thickness of each layer of high refractiveindex material H and low refractive index material L is in a range fromgreater than or equal to 5 nm and less than or equal to 200 nm.

In a nineteenth aspect, the disclosure provides the glass article of anyof the fifteenth through seventeenth aspects, wherein a number ofcoating periods is in a range from greater than or equal to 2 and lessthan or equal to 20, and a thickness of each layer of high refractiveindex material H and the low refractive index material L is in a rangefrom greater than or equal to 5 nm and less than or equal to 100 nm.

In a twentieth aspect, the disclosure provides the glass article of anyof the fifteenth through nineteenth aspects, wherein the layer of highrefractive index material H is selected from the group consisting ofZrO₂, HfO₂, Ta₂O₅, Nb₂O₅, TiO₂, Y₂O₃, Si₃N₄, SrTiO₃ and WO₃.

In a twenty-first aspect, the disclosure provides the glass article ofany of the fifteenth through twentieth aspects, wherein the lowrefractive index material is selected from the group consisting of SiO₂,MgF₂, YF₃, YbF₃, and Al₂O₃.

In a twenty-second aspect, the disclosure provides the glass article ofany of the fifteenth through twenty-first aspects, wherein the glassarticle has a water contact angle of at least 75° after 6,000 abrasioncycles.

In a twenty-third aspect, the disclosure provides the glass article ofany of the fifteenth through twenty-second aspects, wherein the glassarticle has a water contact angle of at least 105° after 6,000 abrasioncycles.

In a twenty-fourth aspect, the disclosure provides the glass article ofany of the fifteenth through twenty-third aspects, wherein the glassarticle has a water contact angle of greater than 90° after 10,600abrasion cycles.

In a twenty-fifth aspect, the disclosure provides the glass article ofany of the fifteenth through twenty-fourth aspects, wherein after 8,000abrasion cycles, scratches on a surface of the glass article are lessthan 2 mm in length.

In a twenty-sixth aspect, the disclosure provides the glass article ofany of the fifteenth through twenty-fifth aspects, wherein a %Reflectance of the glass article after at least 8,000 abrasion/wipingcycles is substantially the same as the % Reflectance of anunabraded/unwiped glass article.

In a twenty-seventh aspect, the disclosure provides the glass article ofany of the fifteenth through twenty-sixth aspects, wherein a %Transmission of the glass article after at least 8,000 abrasion/wipingcycles is substantially the same as the % Transmission of anunabraded/unwiped glass article.

In a twenty-eighth aspect, the disclosure provides a coating apparatusfor coating a substrate with an optical coating and an ETC coating. Thecoating apparatus comprises: a vacuum chamber; a magnetic rotatable domepositioned in the vacuum chamber; at least one e-beam source positionedin the vacuum chamber; at least one thermal evaporation sourcepositioned in the vacuum chamber; and a shadow mask adjustablypositioned on a support within the vacuum chamber.

In a twenty-ninth aspect, the disclosure provides the coating apparatusof the twenty-eighth aspect, wherein the coating apparatus furthercomprises a plasma source positioned in the vacuum chamber.

In a thirtieth aspect, the disclosure provides the coating apparatus ofany of the twenty-eighth through twenty-ninth aspects, wherein therotatable magnetic dome comprises: an opening at a top center of themagnetic rotatable dome; a transparent glass plate covering the openingof the magnetic rotatable dome; and a quartz monitor positioned in anopening in the transparent glass plate for monitoring a deposition rateof coating material deposited in the vacuum chamber.

In a thirty-first aspect, the disclosure provides the coating apparatusthe thirtieth aspect, wherein the coating apparatus further comprises anoptical fiber positioned above the transparent glass plate, wherein theoptical fiber collects light reflected from the transparent glass plateas the transparent glass plate is coated to determine a change inreflectance of the transparent glass plate and thereby a thickness ofcoatings applied to the transparent glass plate.

In a thirty-second aspect, the disclosure provides the coating apparatusof any of the twenty-eighth through thirty-first aspects, wherein themagnetic rotatable dome is attached to a vacuum shielded rotation shaftto facilitate rotation of the magnetic rotatable dome.

In a thirty-third aspect, the disclosure provides the coating apparatusof any of the twenty-eighth through thirty-second aspects, wherein thecoating apparatus further comprises at least one magnetic substratecarrier magnetically attached to the magnetic rotatable dome.

In a thirty-fourth aspect, the disclosure provides a process for makingglass articles having an optical coating in the glass articles and aneasy-to-clean, ETC, coating on top of the optical coating, the processcomprising: providing a coating apparatus having at chamber for thedeposition of an optical coating and ETC coating; providing a rotatabledome within said chamber for magnetically positioning a substratecarrier having an glass substrate thereon that is to be coated, saiddome being concave and having a an opening at the top for the placementof quartz and optical fiber measuring elements; providing within saidchamber source materials for the optical coating and source materialsfor the ETC coating, wherein when a plurality of source materials arerequired for making the optical coating, each of the plurality ofmaterials is provided in a separate source container; providing a glasssubstrate, loading the glass substrate on the substrate carrier andmagnetically attaching the substrate carrier having the glass substratethereon to the dome; evacuating the chamber to a pressure of 10⁻⁴ Torror less; rotating the dome and depositing an optical coating on theglass substrate; ceasing the deposition of the optical coating followingthe deposition of the optical coating, rotating the dome and depositingthe ETC coating on top of the optical coating; ceasing the deposition ofthe ETC coating; and removing the substrate having an optical coatingand an ETC coating from the chamber to obtain a glass substrate havingan optical coating deposited on the substrate and an ETC coatingdeposited on the optical coating.

In a thirty-fifth aspect, the disclosure provides the method of thethirty-fifth aspect wherein the optical coating is a multilayer coatingconsisting of alternating layers of a high refractive index metal oxideand a low refractive index metal oxide, and each high/low index pair oflayers is deemed to be a coating period. The number of periods is in therange of 2-1000. The multilayer coating has a thickness in the range of100 nm to 2000 nm. The ETC materials is an alkyl perfluorocarbon silaneof formula (R_(F))_(x)SiX_(4-x), where R_(f) is a linear C₆-C₃₀ alkylperfluorocarbon, X=Cl or —OCH₃— and x=2 or 3. The alkyl perfluorocarbonhave a carbon chain length in the range of 3 nm to 50 nm. Perfluorinatedethers attached to the above SiX_(4-x) moiety can also be used as ETCcoating materials.

In a thirty-sixth aspect, the disclosure provides the method of thethirty-third through thirty-fifth aspects the optical coating and theETC coating are deposited in a chamber, and the optical coating isdensified during deposition using an ion beam or a plasma. In a furtherembodiment, when the optical coating is an oxide coating, oxygen oroxygen ions are present in the chamber to insure that the stoichiometryof the metal oxide(s) being coated is maintained.

In a thirty-seventh aspect the disclosure is also directed to anapparatus for making a “shadowless” or “shadow free” glass articlehaving an optical coating and an ETC coating thereon, the apparatuscomprising a vacuum chamber having therein a source of the opticalcoating materials and a source of the ETC coating material, a rotatabledome having a plurality of substrate carriers for holding substrates,the substrate carried being magnetically attached to the rotatable dome.

In a thirty-eighth aspect, the disclosure provides a glass articlehaving an optical coating on the surface of the a glass substrate andeasy-to-clean coating on top of the optical coating, said glass articlebeing shadow free across the optically coated surface of the glass;wherein the optical coating is a plurality of periods consisting of alayer of a high refractive index material H, n=1.7-3.0, and a lowrefractive index material L, n=1.3-1.61, the H layer being the firstlayer of each period and the L layer being the second layer of eachperiod; and when the last L layer of the optical coating is not SiO₂, aSiO₂ capping layer having a thickness in the range of 20-200 nm isapplied on top of the plurality of periods. When the last period of theoptical coating is SiO₂ and additional SiO layer having a thickness inthe range of 20-200 nm can optionally be deposited as a capping layer.In one embodiment the number of optical coating periods is in the rangeof 2-1000. In another embodiment the thickness of the optical coatingthickness in the range of 100 nm to 2000 nm. The number of opticalcoating periods is in the range 2-20, and the thickness of each of thehigh refractive index materials and the low refractive index materialsis in the range of 5-200 nm. In another embodiment the number of opticalcoating periods is in the range 2-20, and the thickness of each of thehigh refractive index material and the low refractive index materials isin the range of 5-100 nm. The high index coating material is selectedfrom the group consisting of ZrO₂, HfO₂, Ta₂O₅, Nb₂O₅, TiO₂, Y₂O₃,Si₃N₄, SrTiO₃ and WO₃. The low index coating material is selected fromthe group consisting of SiO₂, MgF₂, YF₃ and YbF₃. In an embodimentAl₂O₃, n−1.5-1.7. is used in place of the low refractive index materialand a capping layer of SiO₂ is applied as the final layer.

In a thirty-ninth aspect, the disclosure provides the method of any ofthe first through twelfth aspects and the glass article of any of thefifteenth through twenty-seventh aspects, wherein a variation in athickness of the optical coating from a first edge of the opticalcoating to second edge of the optical coating of the glass substrate orthe glass article is less than or equal to 3%.

In a fortieth aspect, the disclosure provides the method of any of thefirst through twelfth aspects and the glass article of any of thefifteenth through twenty-seventh aspects, wherein a variation in athickness of the optical coating from a first edge of the opticalcoating to second edge of the optical coating of the glass article isless than or equal to 2%.

In a forty-first aspect, the disclosure provides the method of any ofthe first through twelfth aspects and the glass article of any of thefifteenth through twenty-seventh aspects, wherein a variation in athickness of the optical coating from a first edge of the opticalcoating to second edge of the optical coating of the glass substrate orthe glass article is less than or equal to 1%.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the embodiments describedherein without departing from the spirit and scope of the claimedsubject matter. Thus it is intended that the specification cover themodifications and variations of the various embodiments described hereinprovided such modification and variations come within the scope of theappended claims and their equivalents.

1. A glass article comprising a vacuum-deposited optical coating and avacuum-deposited easy-to-clean coating on top of the optical coating,the glass article being shadow free across an optically coated surfaceof the glass article, wherein: the optical coating comprises a pluralityof periods consisting of a layer of high refractive index material Hhaving an index of refraction n greater than or equal to 1.7 and lessthan or equal to 3.0, and a layer of low refractive index material Lhaving an index of refraction n greater than or equal to 1.3 and lessthan or equal to 1.6, the layer of high refractive index material Hbeing a first layer of each period and the layer of low refractive indexmaterial L being a second layer of each period; and an SiO₂ cappinglayer applied on top of the plurality of periods.
 2. The glass articleaccording to claim 1, wherein a number of coating periods is in a rangefrom greater than or equal to 2 and less than or equal to
 1000. 3. Theglass article according to claim 1, wherein the optical coating has athickness in a range from greater than or equal to 100 nm to less thanor equal to 2000 nm.
 4. The glass article according to claim 1, whereina number of coating periods is in a range from greater than or equal to2 and less than or equal to 20, and a thickness of each layer of highrefractive index material H and low refractive index material L is in arange from greater than or equal to 5 nm and less than or equal to 200nm.
 5. The glass article according to claim 1, wherein the layer of highrefractive index material H is selected from the group consisting ofZrO₂, HfO₂, Ta₂O₅, Nb₂O₅, TiO₂, Y₂O₃, Si₃N₄, SrTiO₃ and WO₃.
 6. Theglass article according to claim 1, wherein the layer of low refractiveindex material L is selected from the group consisting of SiO₂, MgF₂,YF₃, YbF₃, and Al₂O₃.
 7. The glass article according to claim 1, whereinthe glass article has a water contact angle of at least 75° after 6,000abrasion cycles.
 8. The glass article according to claim 1, whereinafter 8,000 abrasion cycles, scratches on a surface of the glass articleare less than 2 mm in length.
 9. The glass article according to claim 1,wherein a % Reflectance of the glass article after at least 8,000abrasion/wiping cycles is substantially the same as the % Reflectance ofan unabraded/unwiped glass article.
 10. The glass article according toclaim 1, wherein a % Transmission of the glass article after at least8,000 abrasion/wiping cycles is substantially the same as the %Transmission of an unabraded/unwiped glass article.
 11. The glassarticle according to claim 1, wherein a variation in a thickness of theoptical coating from a first edge of the optical coating to second edgeof the optical coating of the glass article is less than or equal to 3%.12. The glass article according to claim 1, wherein a variation in athickness of the optical coating from a first edge of the opticalcoating to second edge of the optical coating of the article is lessthan or equal to 2%.
 13. The glass article according to claim 1, whereina variation in a thickness of the optical coating from a first edge ofthe optical coating to second edge of the optical coating of the glassarticle is less than or equal to 1%.
 14. A glass article comprising avacuum-deposited optical coating and a vacuum-deposited easy-to-cleancoating on top of the optical coating, the glass article being shadowfree across an optically coated surface of the glass article, wherein:the optical coating comprises a plurality of periods consisting of alayer of high refractive index material H, and a layer of low refractiveindex material L, the layer of high refractive index material Hcomprising Si₃N₄ and being a first layer of each period and the layer oflow refractive index material L comprising SiO₂ and being a second layerof each period.
 15. The glass article according to claim 14, wherein avariation in a thickness of the optical coating from a first edge of theoptical coating to second edge of the optical coating of the glassarticle is less than or equal to 3%.
 16. A glass article comprising avacuum-deposited optical coating and a vacuum-deposited easy-to-cleancoating on top of the optical coating, the glass article being shadowfree across an optically coated surface of the glass article, wherein:the optical coating comprises a plurality of periods consisting of alayer of high refractive index material H having an index of refractionn greater than or equal to 1.7 and less than or equal to 3.0, and alayer of low refractive index material L having an index of refraction ngreater than or equal to 1.3 and less than or equal to 1.6, the layer ofhigh refractive index material H being a first layer of each period andthe layer of low refractive index material L being a second layer ofeach period.
 17. The glass article according to claim 16, furthercomprising an SiO₂ capping layer applied on top of the plurality ofperiods.
 18. The glass article according to claim 16, wherein a numberof coating periods is in a range from greater than or equal to 2 andless than or equal to
 1000. 19. The glass article according to claim 16,wherein the optical coating has a thickness in a range from greater thanor equal to 100 nm to less than or equal to 2000 nm.
 20. The glassarticle according to claim 16, wherein a number of coating periods is ina range from greater than or equal to 2 and less than or equal to 20,and a thickness of each layer of high refractive index material H andlow refractive index material L is in a range from greater than or equalto 5 nm and less than or equal to 200 rim.
 21. The glass articleaccording to claim 16, wherein the layer of high refractive indexmaterial H is selected from the group consisting of ZrO₂, HfO₂, Ta₂O₅,Nb₂O₅, TiO₂, Y₂O₃, Si₃N₄, SrTiO₃ and WO₃, and wherein the layer of lowrefractive index material L is selected from the group consisting ofSiO₂, MgF₂, YF₃, YbF₃, and Al₂O₃.
 22. The glass article according toclaim 16, wherein the glass article has a water contact angle of atleast 75° after 6,000 abrasion cycles.
 23. The glass article accordingto claim 16, wherein after 8,000 abrasion cycles, scratches on a surfaceof the glass article are less than 2 mm in length.
 24. The glass articleaccording to claim 16, wherein at least one of: a % Reflectance of theglass article after at least 8,000 abrasion/wiping cycles issubstantially the same as the % Reflectance of an unabraded/unwipedglass article; and a % Transmission of the glass article after at least8,000 abrasion/wiping cycles is substantially the same as the %Transmission of an unabraded/unwiped glass article.
 25. The glassarticle according to claim 16, wherein a variation in a thickness of theoptical coating from a first edge of the optical coating to second edgeof the optical coating of the glass article is less than or equal to 3%.